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222                           UFB OF
hygrometer shows a gradually Increasing moisture,
the stars are sometimes veiled by a slight mist, their
light is not steady, and they are occasionally seen to
sparkle about twenty degrees above the horizon. The
breeze blows less violently, and there is often a total
wind calmness. South-south-east of the horizon the
clouds gather, they seem like distant moimtaiiis with
inaccurately defined outlines; they are sometimes
seen to quit the horizon, and scud through the sky
with a speed quite inconsistent with the weakness of
the wind in the lower atmosphere.
Towards the end of March., the southern region of
the atmosphere is lighted by small electric explosions;
they are phosphorescent sparks, limited to a single
group of mist. Now, from time to time, south-west
winds occur., lasting some hours, and are the sure
signs of the approach of the rainy season, which
begins towards the end of April in the Orinocco
The sky then begins to be clouded, the clear blue
disappears, and a uniform grey colour takes its place.
At the same time, the warmth of the atmosphere in-
creases, and not only clouds, but dense mists, cover
the vault of heaven. The howling monkeys make
themselves heard several hours before break of
day; the atmospheric electricity, which, during the
dry season from December to March, had nearly
always averaged 1-72 liaes of the voltaic electrometer
during the day, becomes extremely variable, being
sometimes 03 sometimes 3A lines.
The rainy season is also the season of thunder-
storms. The storm commences two hours after the
- passage of the sun through the meridian., a short time
after the period when the heat has reached its maxi-
mum. The thunder is rarely heard in, the night or
in the morning; but these thunder-storms are alto-
gether only confined to certain river districts having a
peculiar climate.